1) Field of the Invention
The present invention relates to non-destructive inspection and, more particularly, to non-destructive inspection of a workpiece using laser profiling, as well as an associated method.
2) Description of Related Art
Non-destructive testing of structures involves thoroughly examining a structure without harming, or requiring significant disassembly of, the structure. Non-destructive testing is advantageous for many applications in which a thorough inspection of the exterior and/or interior of a structure is required. For example, non-destructive testing is commonly utilized in the aircraft industry to inspect aircraft structures for any type of internal or external damage to the structure. Metallic aircraft structures are typically inspected for corrosion and/or cracking, particularly near fasteners in the structure. Composite structures are typically inspected for any type of damage, such as delamination, occurring anywhere on or within the composite material.
Various types of sensors may be utilized to perform non-destructive testing. One or more sensors may move over the portion of the structure to be examined, and receive data regarding the structure. For example, ultrasonic testing could be used to generate a sound wave through a sensor or probe that is directed towards a part. When there is a flaw in the part, part of the sound wave will reflect back from the flaw and will be detected. A pulse-echo sensor may be utilized to obtain ultrasonic data, such as thickness gauging, detection of laminar defects and porosity, and/or crack detection in the structure. Resonance, pitch/catch or mechanical impedance sensors may be utilized to provide indications of voids or porosity, such as in adhesive bondlines of the structure. In addition, single and dual frequency eddy current probes, utilizing electromagnetic induction, impart and detect eddy currents within a structure so as to identify cracks and/or corrosion, particularly in metallic or other conductive structures. The data acquired by the sensors is typically processed by a processing element, and the processed data may be presented to a user via a display.
Once a defect is located on a part, the part may be repaired or replaced. If the part is to be repaired, the defect is typically machined (e.g., grinding), which requires an additional inspection to determine the amount of material removed to assess the load-carrying capability of the machined part. Generally, a feeler gauge or ultrasonic time-of-flight methods are used to inspect the machined part. Inspecting with feeler gauges are time consuming, lack useful output for analysis, and are prone to human error. Using ultrasonic time-of-flight inspection is more efficient and reliable than inspecting with a feeler gauge, but ultrasonic inspection utilizes a sensor that is much larger than the size of the grind-out area removed during machining.
Current portable inspection systems may be automatic or manual. For example, automatic scanners such as the Mobile Automated Scanner (MAUS®) system, developed by The Boeing Company, are proficient in inspecting relatively flat parts such as wing and fuselage skins. One type of MAUS® system automatically moves along the structure via a track with strategically controlled suction cups, while another type includes handheld sensors and an associated carriage that is moved along the structure via manual motion. As such, the MAUS® system not only scans the part, but also processes the data regarding the structure, and associates the data with the exact location on the part from where the data was obtained. The data is used to create C-scans and B-scans so that flaws or other items of interest may be detected on the surface of the part.
It would therefore be advantageous to provide an inspection system capable of inspecting a workpiece that is accurate and reliable. Also, it would be advantageous to provide an inspection system that is capable of generating images depicting a surface profile of the workpiece. Finally, it would be advantageous to provide a portable inspection system capable of inspecting portions of interest on a workpiece efficiently.